Recently, as image recording materials, materials to form color images are particularly in the main stream, and specifically inkjet recording materials, thermal transfer image recording materials, recording materials using an electrophotographic method, transfer silver halide photosensitive materials, printing inks, recording pens and the like are extensively used. In addition, color filters are used in LCD (liquid crystal display) and PDP (plasma display panel) for displays and in electronic parts such as CCD (imaging device) for photographing equipments. In these color image recording materials and color filters are used coloring matters (dyes and pigments) of 3 primary colors for so-called additive and subtractive color processes to reproduce and record full color images, but it is the case that there is no coloring matter which has absorption characteristics to realize preferable color reproduction areas and is durable to various use conditions, and therefore improvement is strongly desired.
The inkjet recording method has been rapidly spreading and also developing because its material cost is low, rapid recording is possible, noise in recording is less and also color recording is easy. The inkjet recording method includes a continuous method where ink droplets are continuously flown and an on-demand method where ink droplets are flown responding to an image information signal, and its discharging method includes a method where ink droplets are discharged by applying pressure with piezoelectric elements, a method where bubbles are generated in ink by heat to discharge ink droplets, a method using an ultrasonic wave, a method where ink droplets are absorbed and discharged by electrostatic force, or the like. In addition, examples of ink suitable for inkjet recording include a water-based ink, an oil-based ink, a solid (melting-type) ink and the like.
Required points on the coloring matter to be used in an ink suitable for such inkjet recording includes such points that its solubility or dispersibility to solvent is good, high density recording is possible, its hue is good in both monochrome and combination color, it is tolerant to light, heat, and active gases in the atmosphere (oxidizing gas such as NOx and ozone and other gases such as SOx), it has excellent fastness to water and chemicals, its fixation to record-receiving materials is good and therefore it hardly bleeds out, it is excellent in storage stability as ink, it has no toxicity, it is also inexpensively available, and so on. Particularly, strongly desired is a cyan coloring matter which has a good cyan hue, is excellent in light fastness (durability to light), ozone fastness (durability to ozone gas) and moisture fastness (durability under high humidity), and does not exhibit bronze phenomenon (also referred to as bronzing phenomenon). The bronze phenomenon means a glare phenomenon caused by that coloring matter is aggregated on the surface of glossy paper and the like due to association and aggregation of coloring matter or malabsorption of ink into media to give metallic luster. Occurrence of this phenomenon causes inferiority in all views of glossiness, print quality and print density.
Phthalocyanine and triphenylmethane skeletons are representative of the skeleton for water-soluble cyan coloring matters used for an ink suitable for inkjet recording. The typical phthalocyanine coloring matter which is the most widely reported and used includes phthalocyanine derivatives classified into from A to H below.
A: known phthalocyanine coloring matters such as C.I.Direct Blue 86, C.I.Direct Blue 87, C.I.Direct Blue 199, C.I.Acid Blue 249, C.I.Reactive Blue 71.
B: the phthalocyanine coloring matters described in Patent Literatures 1 to 3 and the like (for example, a mixture of Cu—Pc—(SO3Na)m(SO2NH2)n: m+n=a number of 1 to 4).
C: the phthalocyanine coloring matters described in Patent Literature 4 and the like (for example, Cu—Pc—(CO2H)m(CONR1R2)n: m+n=a number of 0 to 4).
D: the phthalocyanine coloring matters described in Patent Literature 5 and the like (for example, Cu—Pc—(SO3H)m(SO2NR1R2)n: m+n=a number of 0 to 4 and m≠0).
E: the phthalocyanine coloring matters described in Patent Literature 6 and the like (for example, Cu—Pc—(SO3H)l(SO2NH2)m(SO2NR1R2)n: l+m+n=a number of 0 to 4).
F: the phthalocyanine coloring matters described in Patent Literature 7 and the like (for example, Cu—Pc—(SO2NR1R2)n: n=a number of 1 to 5).
G: the phthalocyanine coloring matters described in Patent Literatures 8, 9, 12 and the like (the phthalocyanine compound where the substitution position of the substituent is controlled and the phthalocyanine coloring matter where a substituent is introduced at the β-position).H: the benzo pyridoporphyrazine coloring matters having a pyridine ring and a benzene ring which are described in Patent Literatures 10, 13, 14 and the like.
The phthalocyanine coloring matter as typified by C.I.Direct Blue 86 or C.I.Direct Blue 199 used generally and widely at present has a characteristic of having excellent light fastness compared with magenta coloring matters and yellow coloring matters known in general. The phthalocyanine coloring matter is not very preferable as a cyan ink because it has a green tinged hue under acidic conditions. Therefore, when these coloring matters are used as a cyan ink, they are preferably used under neutral to alkaline conditions. However, although the ink is neutral to alkaline, it is possible that the hue of printed matter is largely changed when the record-receiving material to be used is an acidic paper.
In addition, when the phthalocyanine coloring matter is used as a cyan ink, the hue of printed matter is changed to be green tinged as well as color fading occurs due to oxidizing gases such as nitrogen oxide gas and ozone which are often raised as an environmental issue in recent years, resulting in that the print density is decreased.
On the other hand, the triphenylmethane coloring matter is good in hue, but very inferior in light fastness, ozone fastness and moisture fastness.
From here on, when the application field of inkjet recording is expanded and widely used for articles on exhibition of ads and the like, the coloring matter and ink to be used there will be more and more strongly required to have a good hue and be inexpensive as well as to be excellent in light fastness, fastness to active gases in the environment and moisture fastness because they will be more often exposed to light and active gases in the environment (oxidizing gases such as NOx, SOx and ozone, and the like). However, it is difficult to develop a cyan coloring matter (for example, phthalocyanine coloring matter) and a cyan ink satisfying these requirements at a high level. So far, Patent Literatures 3, 8 to 12, 14 and the like disclose the phthalocyanine coloring matters where active gas fastness is imparted, but any cyan coloring matter and cyan ink have yet to be obtained which satisfies all the quality of hue, light fastness, ozone fastness and moisture fastness, does not exhibit the bronze phenomenon, and also can be produced inexpensively. Therefore, the requirements of the market have not yet been satisfied enough.
[Patent Literature 1] JP S62-190273
[Patent Literature 2] JP H07-138511
[Patent Literature 3] JP 2002-105349
[Patent Literature 4] JP H05-171085
[Patent Literature 5] JP H10-140063
[Patent Literature 6] JP H11-515048
[Patent Literature 7] JP S59-22967
[Patent Literature 8] JP 2000-303009
[Patent Literature 9] JP 2002-249677
[Patent Literature 10] JP 2003-34758
[Patent Literature 11] JP 2002-80762
[Patent Literature 12] WO 2004087815
[Patent Literature 13] WO 2002034844
[Patent Literature 14] JP 2004-75986